Frank the Troll Posted March 16, 2016 Share Posted March 16, 2016 Is there much advantage using a 2" barlow with 1.25 lenses, and would it better suit a 2" diagonal? Link to comment Share on other sites More sharing options...
John Posted March 16, 2016 Share Posted March 16, 2016 A 2" barlow needs a 2" diagonal if it's to be used with a refractor, SCT or mak-cassegrain. Some widefield 1.25" eyepieces can have their field of view vignetted by a 1.25" barlow so a 2" barlow would overcome that. Link to comment Share on other sites More sharing options...
Frank the Troll Posted March 16, 2016 Author Share Posted March 16, 2016 11 minutes ago, John said: A 2" barlow needs a 2" diagonal if it's to be used with a refractor, SCT or mak-cassegrain. I have both a frac and a newt, I could use iit on, with a few 1.25 widefield EP's So a 2" diagonal would be worth a punt? Link to comment Share on other sites More sharing options...
Louis D Posted March 16, 2016 Share Posted March 16, 2016 You wouldn't need a diagonal to use it on your newt as long as it has a 2" capable focuser, so give it a go there. The GSO 2" 2x is phenomenal. Make sure it says Taiwan and has a shiny chrome barrel with a black optics section that unscrews from the bottom. Look at the Agena Astro site for an image of it. The FLO ED Deluxe appears to be the poorer Chinese made version, but I could be mistaken. Link to comment Share on other sites More sharing options...
Frank the Troll Posted March 17, 2016 Author Share Posted March 17, 2016 10 hours ago, Louis D said: You wouldn't need a diagonal to use it on your newt as long as it has a 2" capable focuser, so give it a go there. The GSO 2" 2x is phenomenal. Make sure it says Taiwan and has a shiny chrome barrel with a black optics section that unscrews from the bottom. Mine is supposed to be an ED version, but no makers name, the optics does unscrews at the bottom. Compression ring for 2" & 1.25 EP's Yep the newt takes 2" Link to comment Share on other sites More sharing options...
John Posted March 17, 2016 Share Posted March 17, 2016 Those long barrelled barlows can cause some issues when used in a diagonal because you can't insert them all the way so the point of focus of the eyepiece alters quite a bit. Scopes with limited focus travel might not be able to bring them to focus. Some newtonian focusers have a ridge down inside their drawtube that limits the length of barrel that can be inserted. It's worth checking that out as well. I did own one of the GSO / Revelation 2" 2x ED barlows for a while but I can't recall much about it. I probably used it mostly for barlowed laser collimation rather than for viewing. Link to comment Share on other sites More sharing options...
Louis D Posted March 17, 2016 Share Posted March 17, 2016 He could always just unscrew the optics and screw them into the telescope end of his 2" diagonal if infocus is an issue. It should come out close to the same distance (about 100mm give or take for most 2" mirror diagonals). That one appears to be the Chinese clone that doesn't work as well as the Taiwanese one. There was a recent discussion on Cloudy Nights about both. Link to comment Share on other sites More sharing options...
Louis D Posted March 17, 2016 Share Posted March 17, 2016 I found the CN discussion post about the 2" 2X variations here. FLO's definitely looks like the newer Chinese Knight Owl 2" 2x barlow to avoid. I'm not sure who sells the GSO version in the UK. The 1.25" adapter is a totally different design. Link to comment Share on other sites More sharing options...
Ceramus Posted March 17, 2016 Share Posted March 17, 2016 I have the Revelation 2" Barlow and use it both for viewing and laser collimating a SW300p fexitube. I also unscrew the lens off the barrel and use the 2" compression ring with an adaptor for all my EPs. Much better than the the 2 screws barrel supplied with the scope, which has a bit of slop. Link to comment Share on other sites More sharing options...
Frank the Troll Posted March 17, 2016 Author Share Posted March 17, 2016 56 minutes ago, Ceramus said: I also unscrew the lens off the barrel and use the 2" compression ring with an adaptor for all my EPs I shall give that a go on the newt, cheers Better get a 2" diag for the frac then Link to comment Share on other sites More sharing options...
Dave In Vermont Posted March 19, 2016 Share Posted March 19, 2016 I've been hearing good reviews of the GSO 2" Barlow over here in the US on forums for awhile. An example can be found here: http://agenaastro.com/gso-2-2x-ed-barlow-lens.html The price doesn't hurt either. Dave Link to comment Share on other sites More sharing options...
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